Electron tube



3 Sheets-Sheet l Sept. 12, 1939. P. M. G..TOULON ELECTRON TUBE Filed May 27, 1936 Fig.1

Fig. 3

Sept. 12, 1939. P. M. G. TOULON ELECTRON TUBE Filed May 2'7, 1936 3 Sheets-Sheet 2 fig. 8

LVVE/VTOR gm 2- JW 67- 22.61,

Sept. 12, 1939. P. M ca. TOULON ELECTRON TUBE Filed May 27. 1936 3 Sheets-Sheet 3 Patented Sept. 12,1939

UNITED STATES PATENT OFFICE ELIUI'BON TUBE tion of Delaware Application May 2'1, 1936, Serial No. 82,131

In France The present invention relates to a new electronic tube, in which a plurality of grids and a plurality of plates are arranged symmetrically and allow control of the anode currents which are independent of the electronic emission furnished by the cathode.

The control of an electronic current has already been effected in numerous ways with the aid of one or more grids in an evacuated tube.

Whatever the system hitherto employed (electrostatic or electromagnetic control of the electrons), the total quantity of electrons escaping from the cathode is not constant at all times but depends upon the instantaneous voltages applied to the control grids or to the anode, that is, upon the operating conditions of the tube.

This irregularity in the output emitted by the cathode presents numerous drawbacks. In particular, the plate supply system is subjected to the effects of the control grid and of the impedance of the circuits, so that the space charge is not constant. In multi-electrode tubes in particular, where it is sought to accomplish several consecutive effects by means of a single cathode, as is the case with frequency-changing" or "mixing tubes, it is necessary, in order to avoid the inter-action between the different circuits, to add to the control and utilising electrodes, protective electrodes or screen-grids, which reduce the harmful effects of these reactions, without,

however, completely avoiding them.

Various circuits have already been proposed which employ several associated tubes (push-pull circuit for instance) and which partly avoid this defect from the point of view of the external reactions of the tube, but at the cost of a multiplicity of tubes, the charactersitics of which must be exactly matched. In any event, the internal reactions of the tube, that is, the space charge,

the variation of plate impedance etc., are not corrected in this manner.

The present invention has for an object a new method which allows of effecting the control of a plurality of electrodes of a tube by means of other electrodes, without creating external disturbances and, in particular, without causing the intensity of the electronic flux escaping from the cathode to vary, and without creating any variation in the space charge of the tube. For

this purpose, use is made of the well-known properties of deflecting electrodes, that is, electrodes which have the effect of only deflecting the path of the electrons, without modifying the output thereof. The description of an elementary tube has been given in French Patent No. 774,752 of May 31, 1935 the Compagnie Francaise Thomson-Houston, filed June 19, 1934. It is known that, in these tubes, an amplifier can be obtained by making use of the deflecting plates of a tube with a cathodic beam to cause the cathodic beam to impinge on or deviate from the anode. However, contrary to what has been done up to the present day, when the deflecting and collecting electrodes were arranged in the tube without any thought of balance and acted both as deflecting. and retarding electrodes (which had the effect of creating internal and external reactions), according to the invention, the deflecting electrodes are arranged in such a manner that their effects have a zero resultant outside the system, that is, any effect produced in a certain sense on one group of electrodes will be opposed by an effect of opposite sign on another group. Thus, the space charge of the tube is not modified, the total plate current remains constant and the same is the case with the grid current and with the other characteristics of the tube which remain independent of the working conditions.

The objects and the scope of the present invention will be better understood by reference to the accompanying drawings, which represent some particular ways of carrying out the new method.

Fig. 1 serves to illustrate the well-known properties of the push-pull circuit.

Fig. 2 serves to illustrate some properties of the deflecting electrodes of the tubes known up to the present day.

Fig. 3 illustrates the manner in which the new method, forming the object of the invention, provides, with a single tube, a circuit having properties similar to that of Fig. 1 and employing the principle of the deflecting electrodes.

Fig. 4 gives a theoretical explanation of the operation of this tube.

Fig. 5 illustrates the application of the new method to a frequency-changing tube.

Fig. 6 illustrates the application of the new method to a tube with a multi-Mu characteristic.

Fig. 7 shows how it is possible to obtain in a single tube a large number of independent amplifying stages.

Fig. 8 illustrates how it is possible to employ the new method for the complete lay-out of a radio set with a single tube.

Fig. 9 shows in section a constructional embodiment of an electronic tube according to the invention.

All these figures are given only by way of example, as it is quite obvious that the new meth- 0d of balancing the eflects between the electrodes may cover a very large number of modifications corresponding to each particular application of the arrangement.

In Fig. 1, the tube with three electrodes 2, 3, 4 allows of amplifying a weak current furnished by the input circuit I and of obtaining a substantial corresponding current in the output circuit 5 in accordance with the well-known invention of de Forest. If there were no second tube comprising electrodes 8, 9, II, the plate-voltage battery 6 would be affected by the variations of the current in the external circuit 5. These variations also afiect the emission of the cathode 4. To avoid the reactions of the tube on the supply circuit, it has already been proposed to arrange a second tube, such as 8, 9, II, near the first. Arrangements are made so that the input circuit 1 of the second tube is fed in phase opposition to that of the circuit I. Under these conditions, the external current I0 is also in phase opposition to 5. If the two tubes are identical from the point of view of their construction and if the voltage of the grid 2 is continually equal and opposite to that of 8 with respect to a neutral point or to a suitably chosen biasing point, the total current in the external circuits 5 and ill (in the case where the tubes are not saturated) remains almost constant, and the modulation of the system is without harmful effect on the supply circuit 6, that is, the battery does not sufier the consequences of the modulation. This principle of balancing is applied, in accordance with the invention, to tubes containing deflecting electrodes, that is, electrodes having the sole function of deflecting the paths of the electrons and not retarding or stopping them (as was originally done in the de Forest tubes). Owing to the juxtaposition of the two phenomena in a single envelope, it is possible not only to avoid the reactions on the external circuit and on the battery, such as 6, but to combine the cathodes such as 4 and II and consequently avoid the reactions of the operation on the space charge of the envelope.

Fig. 2 serves to illustrate the principle of the deflecting electrodes employed up to the present day. Given a cathode II, an anode I3 brought to a positive potential and formed by a grid, and a second anode I2 also brought to the same positive potential, it is known that the introduction of a grid I4 between the electrodes I2 and I3 allows of varying the ratio of the currents furnished by the electrodes I2 and I3 as a function of the potential of the electrodes I4. This fact is explained by saying that the variation of the potential of the deflecting grid I 4 modifies the space charge in the interval between the grid I4 and the electrode I2, that there is an increase in the dimensions of the neutral zone I5 surrounding the meshes of the grid I4 in proportion to the amount by which the electrodes become more negative and that there is a reduction of the zone I6 available for the passage of the electrons emitted by the filament II and sent through the meshes of the grid I4.

In such a tube, the current furnished by the cathode varies by a relatively small amount when the voltage of the deflecting grid is varied, as the diminution of the current furnished by the electrode I2 is partly compensated by the increase in the output of the electrode I3. However, this compensation is only rather moderate, as the considerable asymmetry which exists between the electrodes I 2 and I3 gives them extremely different characteristics (internal resistance, amplification factor, etc.). In practice, it is suihcient to bring the electrode I3 to a flxed potential, the electrode I2 being the only one which feeds the external circuit. In fact, the electrons leaving the filament II and having passed through the meshes of the electrode I3 must return into contact with the electrode I3 after having approached the deflecting electrode I4, that is, the path of the electrons must be reversed in one case, while, on the contrary, those which reach the electrode I2 continue their path in a straight line, thus contributing in a large measure to increasing the asymmetry of the electrodes I2 and I3. However, in practice, the advantages of such a tube will be appreciated, as the current furnished by the cathode varies relatively little when the voltage of the deflecting grid is varied, and this advantage has rendered great service in radio-set practice. The diminution of the current furnished by the electrode I2 is, in effect, partly compensated by the increase in the output of the electrode I3, and the space charge varies relatively little. However, the compensation is not perfect and the considerable asymmetry in the position of the electrodes i2 and I3 renders the method doubtful in efliciency.

It has also been proposed to employ the principle of the cathode oscillograph, that is, to employ two balanced deflecting electrodes (see French Patent No. 774,752 already mentioned). The use of a single working anode, however, does not cause the asymmetry of the system to disappear. On the other hand, the very great distance which separates the cathodes from the anodes in the apparatus described necessitates the use of very high voltages, and the system is hardly practicaly for producing an amplifier.

According to the invention, there is arranged between the cathode and the anode, not a single deflecting grid, as has hitherto been done (or two deflecting plates of a cathode oscilligraph). but two deflecting grids arranged in spiral form side by side, the different successive meshes being intertwined. These two deflecting grids alternately furnish an action or opposite sense. The anodes arranged opposite these deflecting electrodes are also two in number and are placed in a symmetrical manner. fected by the fact that the difference of potential introduced between the two deflecting grids modifies the distribution of the charges which respectively fall on the two anodes. Given, on one hnad,

that none of the deflecting grids receives electrons and given, on the other, that the whole of the electrons which have left the cathode impinges on the anodes, the sum total of the currents of these anodes remains constant. If these anodes have a space between them which allows certain electrons to escape, the quantity which passes the two anodes also remains constant and independent of the modulation.

The description given above in the case of two anodes and two deflecting grids may also be applied to the case of a large number of anodes and a large number of deflecting grids.

As is shown in Fig. 4, the cathode I I emits electrons; these are accelerated by means of a first auxiliary grid 9 for example, which they clear at great speed. From this moment, the electrons are guided and have a well-determined direction. With the aid of even a weak electrostatic fieldyit is possible to deflect their path. This is precisely the object of the intertwined The modulation is efdeflecting electrodes I! and Il. The most convenient manner of producing these two grids is to give each of them the form of a spiral and to construct these two spirals with the same pitch and with the same diameter and intertwine them. When the deflecting grid II, which, for the clearness of the flgure, has been illustrated by the black spots, is brought to a positive potential, the emitted electrons tend to approach it. Ii, at the same time, the other grid l9 (represented by white spots for the clearness oi the figure) is brought to a negative potential, the electrons tend to digress therefrom. At the anode 2| arranged behind the meshes oi' the grid ll there is convergence; on the contrary, there is divergence at the meshes of the anode 22. In other words, the current tends to be solely furnished by the anode 2|, and the current tends to disappear in the anode 22. However, the sum total of the currents 2| and 22 remains substantially contant, so that the current furnished by the cathode is not affected by the modulation, as was the case with the non-symmetrical tubes hitherto provided.

Fig. 3 shows how the new system 01' deflectin electrodes provides a push-pull amplifying circuit similar to that in Fig. l. The coils 23 and 24 introduce the modulation between the two deflecting grids (as is done by the coils l. and 1 of Fig. l). The amplified current is utilised in the coils 25 and 26 (in the same way as the coils I and I U in Fig. l), but the two systems are placed in the same envelope. However, the cathode 4 was not affected in the same manner as the oathode I l at each instant of the modulation, whereas the cathode I1 is not subjected to the influence of the modulation.

A constructional embodiment of the tube according. to this invention is shown in Fig. 9, the references l8 and I9 representing the two control electrodes of interleaved spiral form which are carried by two insulating rods supported from the foot of the tube. The two interleaved spiral collecting electrodes 2| and 22 are carried by another pair of insulating rods, also supported from the foot of the tube. The foot also carries the cathode II which is heated by the filament 17.

Fig. 4 serves to illustrate the trend of the action of the modulation effected by the intertwined deflecting grids according to the invention. The path of the electrons has been represented by dotted lines and the same elements as in the case of Fig. 3 have been denoted by the same references. Let us assume that the grid is is more negative than the grid l8; as the figure shows, the path of the electrons is deflected by its passage across the modulating grids. The anode 2!, which is situated in a zone of concentration, receives more electrons than the anode 22, which, on the contrary, is situated on a. zone of low electronic density, but the total output of the electrons emitted by the cathode remains constant, although each anode receives a different number of electrons and the modulation is therefore amplified. On the other hand, the number of electrons which have cleared the meshes of the anode grids is not affected by the internal modulation at the anode and this allows of subsequently utilising them for a new purpose.

With the above-described arrangement of the elements, the two control electrodes I8, I! function to separate the electrons flowing toward the anodes 2|, 22 into a plurality of streams. For example, each turn of each of the helical anodes and control electrodes may be considered to be a section '0! the electrode of which it forms a part; the several sections, or turns, being connected together at their ends to form a continuous element. As thus considered, the helicoidal path extending substantially perpendicularly from the cathode and between each adjacent pair of single turns of the two control electrodes may be described as constituting a path for one electron stream and this path may be seen to be parallel to the path of the stream flowing in the helicoidal path perpendicular to the cathode and extending between the next adjacent pairs of single turns of the control electrodes.

It will be understood that the term "section, appearing in the appended claims, is used in its broad sense to denote one of the elemental components of any form of electrode. For example, in the helical form described, even though the electrodes are actually continued helices and the electron stream is actually continuous, to aid in the analysis of the operation of the tube the electrodes may be considered to comprise a plurality of elemental turns or sections and the electron stream may be considered to be made up of a plurality of substantially annular streams bounded by the adjacent sections of the two electrodes. In such a structure, the term section" thus refers to a single elemental component or turn.

As is shown in Fig. 5, the invention can be applied to a frequency-changing heterodyne tube. The deflecting grids 28 and 29 and the symmetrical anodes and 36 contribute to sustaining the heterodyne oscillations. For this purpose, the grids 28 and 29 are connected to an oscillatory circuit 30, 3| and 32. The anodes 35 and 36 are connected to coils 33 and 34 coupled to this oscillatory circuit. Moreover, the voltage of the assembly of deflecting grids 28 and 29 may be modified, for instance, by means of a coil 4| coupled to an oscillatory wave-receiving antennaearth circuit42. This modulation of the assembly of grids 20 and 29 allows of controlling the plate current and thus obtaining an amplification which is completely independent of the modulation, while employing the same tube. The plate 38 receives the current which has passed through the anode 25 and 36. By arranging a grid such as 31, coupled by a condenser such as 44, to the heterodyne oscillatory circuit, the change of frequency can be effected in the same tube, and a suitably tuned oscillatory circuit 43 eventually facilitates coupling. The intermediate-frequency oscillatory circuit 39 is connected to the anode 38.

Fig. 6 illustrates the possibility of application of the new tube for the purpose of obtaining a variable amplification factor. The cathode 41 emits electrons which are deflected by means of A two independent sets of electrodes 4849 and 5ll-5i. The assembly of grids may be controlled by means of the input circuit 46, and the external circuit 56 is connected to the plate 55. The amplication factor of the tube may be varied by modifying the potential of the electrodes and 5| with respect to that of the electrodes 48 and 49. When the electrodes 48 and 50 are brought to the same potential, the amplification factor of the tube is a maximum; vice-versa, if the potential of the electrodes 50 and 5| is increased with respect to that of the electrodes 48 and 49, the amplification factor of the tube is greatly reduced.

Fig. '7 shows how it is possible to obtain in a single tube a plurality of stages of independent amplification. In this figure, the wave-receiving system is shown at IL-6|. The cathode 51 emits 7s electrons. The two grids 64 and 65, which are suitably negatively biased by the battery 58, serve as deflecting electrodes. A potential difference is applied between the two deflecting electrodes 64 and 65 by means of an oscillatory circuit 62-63 coupled to the antenna-earth circuit 60, 6|. The first stage of amplification is obtained with the aid of the anodes 66 and 61 connected to the oscillatory circuit 6869. The electronic flux which escapes through the. anodes 66 and 6'! is strictly constant according to the invention. It is thus possible to place in succession to this first stage a second stage of amplification comprising the grid 70 connected to an oscillatory circuit H coupled to the circuit 6869. The plate 72, which is connected to the output circuit 13, thus receives the energy proceeding from the oscillatory circuit 60-6l and amplified twice.

Fig. 8 illustrates by way of example and in order to show the diversity of application of the invention, how it is possible to employ the new method for the complete lay-out of a radio set with a single tube. Between the cathode i0! and the main anode 99 there are alternately arranged groups of deflecting electrodes and of suitably distributed anodes. The oscillatory antennaearth circuit "I'd-I5 coupled to the circuit 16 acts on the first group of deflecting electrodes ll-J8 which are suitably negatively biased by the bat tery Hi. The first group of anodes "59-83 receives the energy, suitably amplified, in the oscillatory circuit Hill. The heterodyner is arranged between the two grids 8i and 86. This heterodyner is formed by the deflecting electrodes 82 and 83 connected to the oscillatory circuit 504 and by the collecting anodes 84 and 85 connected to the coupling coils I05. The grid 8!, which, through coil Hi3 receives the amplified modulation proceeding from the antenna-earth circuit, supplies this signal energy to the oscillation section comprising grids 82, 83 wherein, by means of electrodes 84, 85, it is modulated by the high frequency oscillations and appears at grid 86 as intermediate-frequency energy. Owing to the 0scillatory circuit !06--l0'l', the deflecting electrodes 87 and 88, with the anodes 89 and 96, effect the intermediate-frequency amplification. The energy is then detected by the system 308-! iii. A first stage of amplification at low frequency is then provided by the deflecting electrodes 92-93 and 94-95. The energy at low frequency is finally amplified by the grid 97. The plate 99 transmits the amplified low frequency energy to the loudspeaker H2.

Fhe grids 96, 98 and H3 are brought to a positive potential and serve as screens.

It is easy to understand that in this manner the reaction between the difierent stages of amplification which are combined in the same tube is completely avoided, and that the new method of the invention allows of obtaining in a single envelope any number of stages of amplification and as complicated a connection as desired.

I claim:

1. Tube comprising a cathode, two interleaved control grids surrounding it, two interleaved collecting grids surrounding the control grids, and a continuous electrode surrounding the whole of the other electrodes.

2. Tube comprising a cathode, two interleaved control grids surrounding it, two interleaved collecting grids surrounding the control grids, an additional protective grid, and a continuous electrode surrounding the whole of the other elec trodes.

3. Electronic tube comprising a single emissivl cathode giving rise to a single electronic stream, at least two intertwined control electrodes having a multiplicity of elements each forming a continuous conductor, at least two intertwined electron-collecting electrodes having a multiplicity of elements each forming a continuous conductor and situated opposite the corresponding element of one of the control electrodes, which latter elements have such a length in the direction of the electronic-stream deflection that, while exerting a deviating action on the electronic stream when a potential is applied'thereto, they do not allow of modifying the total electronic stream intensity traversing them.-

4. Electronic tube comprising a single emissive cathode giving rise to a single electronic stream, at least two intertwined control electrodes having a multiplicity of elements each forming a continuous conductor and arranged in a surface perpendicular to the electronic stream, at least two intertwined electron-collecting electrodes having a multiplicity of elements each forming a continuous conductor and also arranged in a surface perpendicular to the electronic stream, and being situated opposite the elements of the control electrodes, which latter have such a length in the direction of the electronic-stream deflection that, while exerting a deviating eifect on the electronic stream when a potential is applied thereto, they do not allow of modifying the total electronic stream intensity traversing them,

5. Electron tube comprising a cathode, two interleaved control electrodes surrounding it, two interleaved collecting electrodes surrounding these control electrodes, additional electrodes traversed by the electronic stream after its passage through said collecting-electrodes, and a continuous electrode surrounding the whole of the other electrodes.

6. Electronic tube comprising an emissive cathode, a plurality of interleaved control grids, a plurality of interleaved electron-collecting grids,the two groups of grids being arranged .facing each other, and an additional electrode traversed by the electronic stream arranged beyond the said two groups of grids with respect to the cathode, this additional electrode having for object to modulate the total intensity of the electronic stream which has traversed the two groups of grids.

7. In a high-frequency translating system comprising an electron discharge device including a pair of interleaved anodes and a cathode for emitting electrons to said anodes, the method of operation which includes, varying the rate of electron flow to said anodes, separating said electrons into a plurality of streams, each of said streams dividing between a section of one anode and an adjacent section of the other anode, and alternately deflecting each of said streams toward one and then the other of its respective adjacent sections.

8. In a high-frequency translating system, an electron discharge device comprising, a pair of interleaved anodes, each of said anodes comprising a plurality of sections, a cathode for emitting electrons to said anodes, a pair of control electrodes interposed between said cathode and said anodes, means including said control electrodes for varying the rate of electron flow to said anodes and for separating "said electrons into a plurality of streams, each of said streams dividing between-a section of one anode and the adjacent section of the other anode, and means including said electrodes for alternately d each of said streams toward one and then the other of its respective adjacent anode sections.

9. In a high-frequency translating system, an electron discharge device comprising, a pair of interleaved anodes, a cathode for emitting electrons to said anodes, means including a pair of interleaved electrodes interposed between said anodes and said cathode for varying the rate 01' electron flow to said anodes and for separating said electrons into a plurality of streams, each of said streams dividing between a section of one anode and the adjacent section of the other anode, and means including said electrodes for alternately deflecting each of said streams toward one and then the other of its respective adjacent anode sections.

10. In a high-frequency translating system, an electron discharge device comprising a pair of interleaved anodes, each of said anodes including a plurality of sections, a cathode for emitting electrons to said anodes, means including additional electrodes interposed between said cathode andsaidanodesiorvaryingtherateoielectrou flow to said anodes and for separating said electrons into a plurality of streams, each of said streams dividing between a section of one anode and an adjacent section of the other anode, and means including a pair of the additional electrodes interposed between said cathode and said anodes for alternately deflecting each of said streams toward one and then the other of its respective adjacent anode sections.

11. In a high-frequency translating system, an electron discharge device comprising a pair of interleaved anodes, each of said anodes including a plurality of sections, a cathode for emitting electrons to said anodes, a pair of electrodes interposed between said cathode and said anodes, means for varying the rate of electron flow to said anodes and for separating said electrons into a plurality of streams, each of said streams dividing between a'section of one anode and an adjacent section of the other anode, and means including said electrodes for alternately deflecting each of said streams toward one and then the other of its respective adjacent anode sections.

PIERRE MARIE GABRIEL TOUT-ON. 

